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Grade 9 · Chemistry

Grade 9 Chemistry diagnostic

16 questions on general chemistry, chemical reactions, acids, bases & ph, inorganic chemistry, analytical chemistry, physical chemistry and organic chemistry, plus 2 from Grade 8. Answer what you can, then check your answers to see which topics are secure and what to practise next.

16 questions7 topicsAbout 20 minutesSet 1 of 5

Skip a question if you do not know the answer. It is better than guessing, because it shows what to practise.

1General chemistryWhich atom has more valence electrons: strontium (Sr) or potassium (K)?
2General chemistryA model sample has mass 95 g and stated molar mass 42 g/mol. Find its amount. Round to 3 decimal places if needed. Answer in mol.
mol
3Chemical reactionsBalance this equation using the smallest whole-number coefficients: __ CO₂ + __ H₂O → __ C₆H₁₂O₆ + __ O₂. What is the coefficient of H₂O?
4Chemical reactionsIn a sealed container, a 19.3 g sample of a compound decomposes completely into 15.4 g of a gas and one solid product. What is the mass of the solid?
g
5Acids, bases & pHSolution X has pH 3 and solution Y has pH 2. Which is more acidic?
6Acids, bases & pHA solution at 25 °C has a pH of 7. Is it acidic, neutral or basic?
7Inorganic chemistryWhich pair is more likely to have similar main-group chemistry?
8Inorganic chemistryIn neutral MgO, oxygen is assigned −2. What is magnesium’s oxidation state?
9Analytical chemistryA model solution contains 5 g solute and 100 g solvent. Find the solute mass percentage. Round to 3 decimal places if needed. Answer in %.
%
10Analytical chemistryA 297 g sample is 73% desired substance by mass. Find the desired substance mass. Round to 3 decimal places if needed. Answer in g.
g
11Physical chemistryA bond-enthalpy model requires 450 kJ/mol to break bonds and releases 610 kJ/mol forming bonds. Estimate ΔH.
kJ/mol
12Physical chemistryA faster reaction necessarily has a more negative ΔH. Is that valid?
13Organic chemistryA stated repeat unit has two carbon atoms. How many carbons are in 30 such repeat units, ignoring end groups?
14Organic chemistryAn acyclic saturated hydrocarbon has 5 carbon atoms. How many hydrogen atoms does its molecular formula contain? Round to 3 decimal places if needed.

From Grade 8

These questions check skills from the grade below, so gaps can be spotted early.

15General chemistry (Grade 8)Which is a mixture?
16General chemistry (Grade 8)Which property could help separate iron filings from sand in a conceptual example?